https://www.washingtonpost.com/science/ ... detection/
GREENCASTLE, Pa.— The black Labrador circled a giant horizontal metal wheel, sniffing the cans at the end of each spoke before stopping abruptly in front of one. Head up and ears pricked, Blaze froze, staring intently ahead.
“That’s the grail!” exclaimed Cynthia Otto, director of the Penn Vet Working Dog Center at the University of Pennsylvania School of Veterinary Medicine.
“That’s amazing! Just amazing!”
Kibble tumbled out of a dispenser, and Blaze bounded across the small training facility to devour it, tail-waggingly pleased with his reward but unaware of why his olfactory prowess so delighted the human onlookers...